Such an optical apparatus frequently includes, in order to suppress an image shake due to hand jiggling or the like, the optical image stabilizer (hereinafter simply referred to as image stabilizer) that moves a correction lens in a direction different from that of the optical axis (e.g., a pitch direction and a yaw direction which are orthogonal to the optical axis).
Japanese Patent Laid-Open No. 8-184870 discloses an image stabilizer in which a correction lens is supported by springs and is held at a neutral position in a non-image stabilizing operation state, and the correction lens is moved with a driving force generated by an actuator against the forces of the springs in an image stabilizing operation state. In such a spring-hanging-type image stabilizer, it is not necessary to detect the position of the correction lens, that is, it is not necessary to include a position detection mechanism for the correction lens, which easily reduces the size and manufacturing cost of the image stabilizer.
However, in the spring-hanging-type image stabilizer, the increase of the weight of the correction lens makes it difficult to hold the correction lens at the neutral position only by the springs. This makes an image shift amount on an image-forming plane large in the non-image stabilizing operation state.
On the other hand, when a spring constant of the springs is increased in accordance with the increased weight of the correction lens, the driving force required to drive the correction lens against the spring force in the image stabilizing operation state is increased, which increases the size of the actuator and a battery consumption amount.
Further, even when the correction lens has a small weight, increasing the driving stroke of the correction lens for the purpose of obtaining an image stabilizing effect for a certain degree of large shake increases power supplied to the actuator, which increases a battery consumption amount.
In order to solve such disadvantages, Japanese Patent Laid-Open Nos. 2-162320 and 11-167074 disclose a method to move the correction lenses having optical powers opposite to each other in directions opposite to each other to reduce the weight of each of the correction lens or to suppress the driving stroke thereof.
However, in the image stabilizer disclosed in Japanese Patent Laid-Open No. 2-162320, a long link mechanism for balancing the correction lenses having the opposite optical powers extends in the optical axis direction, which increases the size of the image stabilizer. Furthermore, the correction lens can rotate around the center on the optical axis via the link mechanism. If the correction lens displaces in the optical axis direction due to the rotation thereof, a focal shift may occur.
The image stabilizer disclosed in Japanese Patent Laid-Open No. 11-167074 is used for binoculars. This image stabilizer uses a motor and a feed screw to drive the correction lens, which makes it difficult to achieve high-speed driving and good positional accuracy of the correction lens. In addition, this image stabilizer drives separate correction lenses in the pitch direction and the yaw direction, so that it is difficult to reduce the size.